The study will include 20 boys aged 8 to 10 years old, regularly enrolled in local schools and directed to the research through advertisement in the media, contact with schools or directly referred to the Attention Deficit/Hyperactivity Program (ProDAH/HCPA) by primary care services for assessment and treatment. Only children with a primary diagnosis of ADHD or with the comorbidity ADHD + reading disorder or ADHD + ODD will be included. Only drug-naïve subjects will be apt to participate in the study.